One of the most closely guarded trade secrets in the history of commerce may be a secret no more: the radio show "This American Life" thinks it has found the exact recipe for the world's most popular soft drink in a 1979 newspaper article.

According to the show's host, Ira Glass, the drink's secret flavoring component, which was created by pharmacist John Pemberton in 1886, is something called "Merchandise 7X." The show's staff recently stumbled across the February 8, 1979 edition of the Atlanta Journal-Constitution, which published an article on page 28 about a leather-bound notebook that once belonged to Pemberton's best friend, another pharmacist in the Atlanta area named R. R. Evans. The notebook contained a number of pharmacological recipes--but the main entry, for students of commercial history, was what's believed to be the exact recipe for the soft drink: all of the ingredients listed with the exact amounts needed to whip up a batch.

The Journal-Constitution piece also featured a photo of the page in Evans' notebook detailing Coke recipe--essentially revealing the recipe to the world. But since 1979 well antedated the explosion of digital media, the photograph of the recipe didn't travel far beyond the Atlanta area.

Coke's recipe is one of the most closely guarded secrets in American commerce, steeped in cloak-and-dagger lore. After businessman Asa Griggs Candler bought out Pemberton--who also conjured up cough medicines and blood purifiers, among other things--in 1887 for $2,300, the exact recipe for 7X was placed in the vault in an Atlanta bank. It's been reported that only two company employees are privy to its ingredients and how they're mixed at any given time--and that those two aren't allowed to travel together out of fear that a traveling accident might take both of their lives.

According to company historian Mark Pendergrast, Candler was so paranoid about the recipe leaking out of his proprietary control that he would go through the company mail himself to prevent any employees from seeing invoices that might tip off its ingredients.

"It's this carefully passed-on secret ritual," Pendergrast told Glass, "and the formula is kept in a bank vault at Sun Trust, which used to be the Georgia Trust Company."

After Pendergrast reviewed the recipe in the 1979 newspaper photo, he concluded that it could well be the real deal: "I think that it certainly is a version of the formula," he said, adding, "It's very similar to a formula that I found" in one of John Pemberton's notebooks when he was doing research for the book. Coke, for its part, denies that the security of its secret formula has been breached. "Many third parties, including 'This American Life,' have tried to crack our secret formula," company spokeswoman Kerry Tressler said. "Try as they might, they've been unsuccessful." Coke's archive director Philip Mooney told "This American Life" that the recipe may well have been a "precursor" to the prized formula, but probably wasn't the version that "went to market."

So what's the secret to making Coke? Well, here's what was written in the notebook:

Pemberton had reportedly hit upon the formula for Coke in an attempt to overcome the addiction to morphine he contracted after the Civil War, so it's perhaps not surprising that, in addition to alcohol, the drink originally contained Coca leaves laced with cocaine. After Atlanta passed a local prohibition ordinance in the 1890s, the company took the booze out of the formula, and the company has used cocaine-free coca leaves since 1904.

When the beverage debuted in Atlanta-area pharmacies owned by friends of Pemberton, marketers pronounced it "a shot in the arm"-- while Pemberton himself hailed it as a cure for cure pain, impotence and headaches. In our more enlightened age, of course, we know that Coke "adds life"--together with a dollop or two of neroli and nutmeg oil.

CORRECTION: This post originally called "This American Life" "NPR's 'This American Life'." However, while the show does air on NPR, it is produced by Chicago Public Radio and distributed by Public Radio International.